Provide basic policy that core reviewers can apply to outstanding reviews. As
always, it is up to the core reviewers discretion on whether a patch should or
should not be abandoned. This policy is just a baseline with some basic rules.

If a proposed patch has no feedback but is +1 from CI, a core reviewer should
not abandon such changes.

If a proposed patch a given a -1 by a reviewer but the patch is +1 from CI and
not in merge conflict and the author becomes unresponsive for a few weeks,
reviewers can leave a reminder comment on the review to see if there is
still interest in the patch. If the issues are trivial then anyone should feel
welcome to checkout the change and resubmit it using the same change ID to
preserve original authorship. Core reviewers should not abandon such changes.

Feel free to restore your own patches. If a change has been abandoned
by a core reviewer, anyone can request the restoration of the patch by
asking a core reviewer on IRC in #tripleo on freenode or by sending a
request to the openstack-dev mailing list. Should the patch again
become stale it may be abandoned again.